In high performance electronic computing systems, the heat-generating active components need to be cooled in order to keep the component temperatures within acceptable limits. Heat is removed from a processor die made from silicon or other material by contacting the face of the die with a thermal sink through a first thermal interface material (TIM1). In most applications, this thermal sink is a module lid or heat spreader, in which case a second thermal interface material (TIM2) is used to make contact with a liquid-cooled cold plate or air-cooled heat sink.
In other applications referred to as “bare die attach,” the cold plate or air-cooled heat sink is contacted directly to the heat generating chip through the TIM1, and the TIM2 is eliminated. In all cases, the processor die will have a limit on the maximal local force which it can tolerate before being damaged. Most systems limit the local force by using a mechanically compliant TIM1 to even out the force seen by the die. Bare die attach with no TIM2 is used when better thermal performance is required. For cases where a stiffer or thinner TIM1 is desired to further improve thermal performance, a flexible cold plate or heat sink can be used.
Such existing methods can do a good job of reducing local force inequalities applied to the processor die, when a single thermal sink is contacted to a single chip or a single group of closely spaced chips of relatively uniform height.